1. Field of the Invention
The present invention relates in general to a method and a system for coating a coating liquid on the surface of a member to which the coating liquid is to be applied by relatively moving a coating head and the member. In particular, such a method and a system are suitably used when manufacturing a color filter for use in a color television, a personal computer, and the like.
2. Related Background Art
Heretofore, the coloring method, the pigment dispersion method, the electrocoating method, the printing method and the like are well known color filter manufacturing methods. In each of these methods, however, in order to color the three primary colors R, G and B, the same process must be repeated three times. For this reason, since the number of processes is large, the yield is reduced, and the cost is increased.
In addition, in the case of the electrocoating method, the shape of the formable pattern is limited, and hence it is difficult to apply this method to the manufacture of TFTs. In addition, in the case of the printing method, the resolution becomes poor and hence it is difficult to cope with pattern scale down (shrinking).
Then, in order to address the above-mentioned disadvantages, a technology in which an ink jet is jetted onto a glass substrate to form the pattern of the filter (refer to Japanese Patent Application Laid-Open No. 59-75205 and the like) has been proposed. In this technology, since the pixels of three primary colors R, G and B are simultaneously formed, it is possible to greatly shorten the process. However, in this technology, since the primary colors R, G and B are painted in droplets, a phenomenon called color mixing occurs in which the primary colors are mixed with one another.
In order to prevent such color mixing, in Japanese Patent Application Laid-Open No. 8-75916, the layer (the ink acceptable layer) made of resin or resinous composition which has the ink acceptability and which is cured or which has the remaining amount of hydrophilic groups thereof decreased by the application of light, heat or the like thereto is formed on the substrate; at least a part of the non-pixel area defined between the pixels is cured or the remaining amount of hydrophilic groups is decreased to provide ink repellency to form a color mixing preventing layer (the ink repellency layer). In this way, lack of color in the pixels, spreading of the ink to adjacent pixels and color mixing are prevented.
Also, in the process of manufacturing the color filter, in addition to the above-mentioned ink acceptable layer, the protection layer (the over coat layer) for protecting the colored surface, which is made of resin, is also formed. In addition, a photosensitive material which is used to etch a black matrix for higher contrast promotion or a higher degree color when carrying out the display using the color filter is also made of resin. Also, the black matrix itself may be formed of resin (the resin matrix) in some cases.
Now, as for the coating liquid which is used to form such a resin layer or a resin film, normally, a liquid is employed which is obtained by mixing two or more liquid components with one another at a fixed ratio. Heretofore, such a mixed liquid is preliminarily produced on a mass scale taking half a day or a day, for example, and is stored in a coating material tank 41 as shown in FIG. 4 in order to be later supplied from the tank 41 to a member 7 to which the coating liquid is to be applied. In FIG. 4, reference numeral 5 designates a nozzle; reference numeral 6 designates a coating film; reference numeral 7 designates a member to which the coating liquid is to be subjected to a coating; reference numeral 8 designates a carrier stage; reference numeral 41 designates a coating material tank; reference numeral 42 designates a pipeline; reference numeral 43 designates a quantity measuring pump; reference numeral 44 designates a shut-off valve; reference numeral 45 designates a filter; and reference numeral 54 designates a slit.
In this connection, there arises a problem in that the viscosity of the mixed liquid as described above changes with the passage of time, and hence it is difficult to control the thickness of the coating liquid; a gel or the like is typically generated in the coating liquid supplying route, thereby generating coating defects. As a result, cleaning of the route is required at a high frequency, the frequency of the mixing and the frequency of filling the coating material tank 41 with the coating material are both increased due to the limitation of the pot life (the time interval for use), the mixed liquid is wasted and so forth.
In light of the foregoing, the present invention was made in order to solve the above-mentioned problems associated with the prior art. It is therefore an object of the present invention to promote labor saving and high reliability in coating with a coating liquid which has been obtained by mixing a plurality of different liquids with one another.
In order to solve the above-mentioned problems associated with the prior art, according to one aspect of the present invention, there is provided a coating method in which the coating liquid is discharged on the surface of a member to which the coating liquid is to be applied by moving relatively a coating head and the member to form a coating film, characterized in that the process of mixing plural kinds of coating liquid with one another and the process of supplying the resultant mixed liquid to the coating head are substantially simultaneously carried out.
In addition, according to another aspect of the present invention, there is provided an application system having: a coating liquid supplying apparatus for supplying the coating liquid to a coating head having a slit for discharging therethrough the coating liquid; a stage for holding a member to be coated with the coating liquid; and driving means for moving relatively the stage and the coating head, characterized in that the coating liquid supplying apparatus includes: mixing means for mixing equal to or more than two different coating liquids with one another at a fixed ratio; and mixed liquid supplying means for supplying the resultant mixed liquid to the coating head.
Further, according to still another aspect of the present invention, there is provided a coating system for applying a two liquid mixed type application liquid to the surface of a member to be coated with the coating liquid to form a coating film, characterized in that a coating liquid supplying apparatus includes: first quantity measuring supply means for supplying a first coating liquid from a first tank to mixing means at a first flow rate; second quantity measuring supply means for supplying a second coating liquid from a second tank to the mixing means at a second flow rate; and mixed liquid supplying means for supplying the mixed liquid which has been obtained in the mixing means to a coating head at a third flow rate.
According to the present invention, in coating with the coating liquid which has been obtained by mixing a plurality of different liquids with one another, the process of mixing the liquids can be carried out right before the coating, and hence coating becomes possible without any of the above-described pot life limitations. In addition, it is possible to prevent the generation of gel and the like in the coating liquid supplying route, and also it is possible to prevent any of the coating defects resulting therefrom.